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NEW! Ultimate C/S Prop Wrench Anti Splat Aero

Impressed

I haven't bought a single product from Anti-Splat (yet!) but I have been very impressed with the solutions you have created for the problems we have. The videos are great and the straight forward approach is cool.

A "Billy Mays" approach on the videos would be hillarious though! Keep up the good work.

PS - Where do we buy "Genius at Work" shirts???
 
Hello Allen,

Congrats to Antisplataero! I truly appreciate the work you folks are doing to improve the safety....and fun of this 'RV' hobby that so many people enjoy. I think your products are above and beyond....great job!

I just watched your video for the prop wrench. I routinely install and remove Hartzell and Whirlwind C/S propellers and have my own 'system' for this task that works quite well. That said...I love your wrench....the extra width of your tool will eliminate how the typical wrenches (even the good ones) open with the higher torque values. I especially like the ratchet motion of your new wrench.....that's what sold me....wonderful :).

Good Luck and Keep Em' Comin'!!



Ultimate C/S Prop Wrench
We have completed our testing and development on this product and now are offering them for sale. Please have a look at the demonstration video below. If you have a constant speed propeller or work on airplanes you will definitely want one of these. Let us know your opinions. Regards all, Allan
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http://antisplataero.com/Videos.html
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http://antisplataero.com/Products.html
 
Nice Job...will definately put one in my tool box - now please make me one for a SAE30 spline C/S Ham Standard! :)

Cheers,
Stein
 
Wow, wish I had this a few days ago. Think I want one for next time. One question Alan:

You mention in the video that the 3inch length results in a multiplier of 0.8 to get the torque value. Is this true regardless of the toque wrench used? If so, this seems to imply that all toque wrenches are the same length. Is that really true?

Thanks,

Erich
 
Wow, wish I had this a few days ago. Think I want one for next time. One question Alan:

You mention in the video that the 3inch length results in a multiplier of 0.8 to get the torque value. Is this true regardless of the toque wrench used? If so, this seems to imply that all toque wrenches are the same length. Is that really true?

Thanks,

Erich

Hi Erich;
The torque wrench measures foot pounds. The prop tool we made if installed on the torque wrench in a straight line increases the torque arm. To make the readings come out correct the .8 multiplier is used. Am alternative method is to install the prop wrench on the torque wrench at a 90 degree angle and use no multiplier as nothing will be dimensionally any different. All torque wrenches aren't the same length but the length change only effects how hard you need to pull to get to your desired number. All foot pound torque wrenches are the same in function and measure foot pounds regardless of their overall length. Thanks, Allan:)
 
Hi,

This looks like a great tool. Will it work on the Whirlwind prop too?

Yes! The WW prop is a Hartzell compact hub or exact copy of one. That is what I have on my airplane and is the same hub as in the video. Thanks, Allan
 
Hi Erich;
The torque wrench measures foot pounds. The prop tool we made if installed on the torque wrench in a straight line increases the torque arm. To make the readings come out correct the .8 multiplier is used. Am alternative method is to install the prop wrench on the torque wrench at a 90 degree angle and use no multiplier as nothing will be dimensionally any different. All torque wrenches aren't the same length but the length change only effects how hard you need to pull to get to your desired number. All foot pound torque wrenches are the same in function and measure foot pounds regardless of their overall length. Thanks, Allan:)

Allan,
Looks like a great tool, already placed my order. However, I'm no math wiz but what you're saying contradicts the standard formula when using an extension:

Wrench setting = desired torque x wrench length / (wrench length + extension length)

So I guess I don't get it either :confused:
 
Torque multiplier

The torque is accurately applied at the end of the torque wrench. Since while using this tool the torque wrench is actually 3" from the bolt you are torquing, there is an additional 3" moment arm to factor into the equation. Converting the 3" to feet (so as to apply accurately to the the "foot pound" units used) gives 3/12 which is .75 which they round to .8.

If you need to torque a bolt to 100 ft/lb and your wrench is one foot long, you will need to apply 100 pounds to the handle to reach the value. If your torque wrench was 2 feet long you only need apply 50 lbs of force to the handle to reach the same torque. The wrench scale is calibrated for the length.

Since you are introducing additional moment arm, you must manually account for this or you will end up overtorquing by this 25%. In this case you would set your torque wrench to 75 ft/lb when using the prop wrench. When the torque wrench indicates 75 ft/lb of torque, the bolt will be at 100 ft/lb.
 
Example was for a 12 inch wrench length...

Wrench torque = desired bolt torque * (wrench length / total length)

For a wrench length (to the handle centerline) of 12" with a 3" extension you have (12 / 15) or .8
 
I agree with Walt, the angle at which the wrench attaches to the torque wrench should make no difference - the multiplier should stay the same regardless of the angle. You still have a 15" arm rather than the standard 12" arm.

Edit: I stand corrected, the angle DOES matter.

Greg
 
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Wrench torque = desired bolt torque * (wrench length / total length)

For a wrench length (to the handle centerline) of 12" with a 3" extension you have (12 / 15) or .8

Correct.

Total new length assuming the wrench starts at 12", becomes 15".

Try working the problem from the other direction, multiply the arm of 15" times .8.

See what you get.

Here is one other--------- 100# x 12" = 1200in/lb. 80# x 15"= 1200in/lb.
 
Allan,
Looks like a great tool, already placed my order. However, I'm no math wiz but what you're saying contradicts the standard formula when using an extension:

Wrench setting = desired torque x wrench length / (wrench length + extension length)

So I guess I don't get it either :confused:

Hello Walt;
This is sometimes a little confusing and is not as obvious as it first seems. Here is a link to a calculator that will help. Check it out, it's a nice tool. Allan
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http://www.engineersedge.com/manufacturing_spec/calculator/torque_adapter_extension.htm
 
Wrench torque = desired bolt torque * (wrench length / total length)

For a wrench length (to the handle centerline) of 12" with a 3" extension you have (12 / 15) or .8


Im sure Im being dense, but the above seems to be confirming my original concern - that wrench length matters, and they may not all be the same.

Assuming there is some variation in length between different brands of torque wrenches, how can it be true that it doesnt matter which brand I use (assuming all are in ft lbs)?

Ready to buy as soon as my brain untangles...

P.S. just checked the informative link in the above post - that seems to confirm what I am saying. The "L" value or length of the torque wrench without the extension affects the torque that is applied. Unless ft-lbs torque wrenches are all the same length, the 0.8 factor would not seem to be a universal factor to be applied. No?

erich
 
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Im sure Im being dense, but the above seems to be confirming my original concern - that wrench length matters, and they may not all be the same.

Assuming there is some variation in length between different brands of torque wrenches, how can it be true that it doesnt matter which brand I use (assuming all are in ft lbs)?

Ready to buy as soon as my brain untangles...

erich

Erich... You are correct, different length wrenches will require a different multiplier, not all wrenches are 12". My 1/4, 3/8, and 1/2" torque wrenches are not the same length!

Unless someone can prove me wrong mathmatically, length of the wrench does matter. The .8 only applies to a 12" wrench.

Here's an even nicer calculator to use:

http://www.freeinfostuff.com/TorqueExtension/TorqueExtension.htm
 
I agree with Walt, the angle at which the wrench attaches to the torque wrench should make no difference - the multiplier should stay the same regardless of the angle. You still have a 15" arm rather than the standard 12" arm.

Greg

The angle actually makes all the difference. Go to the link below and scroll down to the section that reads;
C - The Extension is Not Lined up With the Wrench.
Now enter the numbers in different angles and it will become clear. Regards, Allan:)
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http://www.freeinfostuff.com/TorqueExtension/TorqueExtension.htm
 
I agree with Walt, the angle at which the wrench attaches to the torque wrench should make no difference - the multiplier should stay the same regardless of the angle. You still have a 15" arm rather than the standard 12" arm.

Greg

Just to clarify, I never said angle didn't matter, it does.
 
Im sure Im being dense, but the above seems to be confirming my original concern - that wrench length matters, and they may not all be the same.

Assuming there is some variation in length between different brands of torque wrenches, how can it be true that it doesnt matter which brand I use (assuming all are in ft lbs)?

Ready to buy as soon as my brain untangles...

P.S. just checked the informative link in the above post - that seems to confirm what I am saying. The "L" value or length of the torque wrench without the extension affects the torque that is applied. Unless ft-lbs torque wrenches are all the same length, the 0.8 factor would not seem to be a universal factor to be applied. No?

erich

This is just a case of miscommunication! Remember we are talking about foot lb. torque wrenches and yes they are all calibrated exactly the same to read in foot lbs. regardless of handle length. The longer the handle, the less force required of you to achieve your desired torque. The torque wrench is measuring the force applied to the bolt, not to the handle. If you use a 36" cheater bar on your torque wrench that only means you do not pull as hard.
 
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my 01 cent worth

Allan is right, the .8 was an example. The calculators work. and a wrench at 90 degrees to the extension negates the need for a correction. happy building;)

bird
 
Hi Erich;
The torque wrench measures foot pounds. The prop tool we made if installed on the torque wrench in a straight line increases the torque arm. To make the readings come out correct the .8 multiplier is used. Am alternative method is to install the prop wrench on the torque wrench at a 90 degree angle and use no multiplier as nothing will be dimensionally any different. All torque wrenches aren't the same length but the length change only effects how hard you need to pull to get to your desired number. All foot pound torque wrenches are the same in function and measure foot pounds regardless of their overall length. Thanks, Allan:)

Growing weary of this as Im sure are others, but I never read/heard Allan say that the 0.8 was only an example. The quote above from Allan's earlier post, as well as the product video, seems to say that if your torque wrench measures in ft lbs, that 0.8 is the correct multiplier. I say, (as does Walt I believe) that is not necessarily the case. Ya gotta measure the length of your torque wrench and if its not 12 inches, you better do the math or plug in the numbers to the handy calculator web site that was posted to see what value to set your wrench at when using the extension.

Do you agree Allan?

And for the record, love you man, product on order :)

erich
 
Growing weary of this as Im sure are others, but I never read/heard Allan say that the 0.8 was only an example. The quote above from Allan's earlier post, as well as the product video, seems to say that if your torque wrench measures in ft lbs, that 0.8 is the correct multiplier. I say, (as does Walt I believe) that is not necessarily the case. Ya gotta measure the length of your torque wrench and if its not 12 inches, you better do the math or plug in the numbers to the handy calculator web site that was posted to see what value to set your wrench at when using the extension.

Do you agree Allan?

I agree with Allan. If a cheater bar is used to extend the length of any length torque wrench...........at the handle end, then the torque value remains the same. Would we need to change settings, just because we have longer or shorter (human) arms?
 
Growing weary of this as Im sure are others, but I never read/heard Allan say that the 0.8 was only an example. The quote above from Allan's earlier post, as well as the product video, seems to say that if your torque wrench measures in ft lbs, that 0.8 is the correct multiplier. I say, (as does Walt I believe) that is not necessarily the case. Ya gotta measure the length of your torque wrench and if its not 12 inches, you better do the math or plug in the numbers to the handy calculator web site that was posted to see what value to set your wrench at when using the extension.

Do you agree Allan?

And for the record, love you man, product on order :)

erich

All foot lb. torque wrenches are the same regardless of handle overall length. The overall length only effects how hard you need to pull on it. on a foot lb. torque wrench the .8 multiplier is exactly and always the number. It is not rounded off and it never changes as long as the crows foot or our tool is 3" and in installed straight. If you install it on the torque wrench at 90 degrees the multiplier is 0, at a 45 degree angle it is .9. This is simple math and does not change.
 
So you are saying if it is a ft-lb wrench: (12")/(12"+3") = 0.8

And if it is a newton-meter wrench: (39.37")/(39.37"+3") = 0.929

And if it is an inch-lb wrench: (1")/(1"+3") = 0.25

I don't think so!

As a bunch of folks have pointed out, your correction factor should be (wrench length in inches) / (wrench length in inches + 3"), it doesn't matter what the scale is calibrated in. A lot of torque wrenches have both metric and SAE scales for example.

Of course "wrench length" doesn't include the length of any cheater bar. It is the designed length of the wrench, from the handle pivot to the socket axis.

--Paul
 
Interesting...

All foot lb. torque wrenches are the same regardless of handle overall length. The overall length only effects how hard you need to pull on it. on a foot lb. torque wrench the .8 multiplier is exactly and always the number. It is not rounded off and it never changes as long as the crows foot or our tool is 3" and in installed straight. If you install it on the torque wrench at 90 degrees the multiplier is 0, at a 45 degree angle it is .9. This is simple math and does not change.


It is my understanding that torque wrenches are calibrated from the center of the handle and that is the lever distance to be used for accurate torque and extension calculation. Where you grip effects the amount of bending moment within the tool which is properly accounted for only at the calibration point; middle of the handle. I have never seen reference to a lever length other than from the calibration point to the ratchet head.

If two similar torque wrenches, one long and one short were both calibrated at 12" the lever calculation would be the same (or very similar), however, they are calibrated at their respective handles to generate an indicated torque at the ratchet head which impacts the internal pawl size or beam arm mechanism along with the bending of the wrench itself.

Always torque from the calibration point, the handle... never use a cheater bar to make it easier to get a torque value, at least if you hope for an accurate torque.
 
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Assume that a nut needs exactly a one quarter turn more(90 degrees), to hit the exact specified torque value. Let's say the torque wrench is 12" long.

Get a ten foot cheater bar, and it's still going to be just a 90 degree movement. The "push" required at the end of the ten foot bar, is much less than that at 12", but the traveled distance is much farther. Works just like a block & tackle. Whether it's 12" or ten feet, the torque value of the nut, remains the same.
 
It is my understanding that torque wrenches are calibrated from the center of the handle and that is the lever distance to be used for accurate torque and extension calculation. Where you grip effects the amount of bending moment within the tool which is properly accounted for only at the calibration point; middle of the handle. I have never seen reference to a lever length other than from the calibration point to the ratchet head.

If two similar torque wrenches, one long and one short were both calibrated at 12" the lever calculation would be the same (or very similar), however, they are calibrated at their respective handles to generate an indicated torque at the ratchet head which impacts the internal pawl size or beam arm mechanism along with the bending of the wrench itself.

Always torque from the calibration point, the handle... never use a cheater bar to make it easier to get a torque value, at least if you hope for an accurate torque.

The cheater bar was only stated to demonstrate a point or principal, not a suggestion. As for torque wrenches that are calibrated from the handle, the only ones that are sensitive to this are the old school bending beam type that depend on the entire beam length to flex giving the indication. That type has a pivoting handle to address this issue. None of this has anything to do with the .8 multiplier or click type, gauge pull type, flex shaft internal, twisting shaft or load cell type wrenches. If the wrench is in foot pounds the correction factor with our wrench is .8, if in inch pounds it is .8 X 12. Thanks, Allan:D
 
problem is in measurement...

Assume that a nut needs exactly a one quarter turn more(90 degrees), to hit the exact specified torque value. Let's say the torque wrench is 12" long.

Get a ten foot cheater bar, and it's still going to be just a 90 degree movement. The "push" required at the end of the ten foot bar, is much less than that at 12", but the traveled distance is much farther. Works just like a block & tackle. Whether it's 12" or ten feet, the torque value of the nut, remains the same.

The problem is with the torque measurement. With and without the cheater bar the wrench will indicate that the specified torque is reached at different physical points... The method of measurement is pretty finicky. A cheater bar will place a levered load onto the wrench itself applying both an upward force and downward force (assuming a tube shaped cheater is slipped over the wrench) which will impact the measured torque at the head. How much will depend on how deep the cheater is inserted, how much force leverage is being applied, how different the material and physical properties of the wrench and cheater are for bending...

in the end none of this likely matters much though since we are dealing with pretty broad torque ranges but don't get fooled into thinking that the torque you dial up or read is pin point accurate. CDI calls calibration less than 20% 'minor'.

Good technique with a well calibrated wrench is still likely +/- 5%. It would not surprise me to see a typical tool box torque wrench with poor technique off 30% or more. Even at that error most mid torques values that we are dealing with are pretty safe. I recall a discussion here where someone was consistently braking off AN3 bolts with their torque wrench... turned out he was using ftlbs rather than inlbs... not surprising that he was breaking bolts.



To get this thread back on track...

Great solution for prop bolts! I ordered one this morning ;)
 
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Wrench torque = desired bolt torque * (wrench length / total length)

For a wrench length (to the handle centerline) of 12" with a 3" extension you have (12 / 15) or .8



That is correct, this is why the .8 multiplier. Thanks, Allan


Still cant see the logic behind how the 0.8 can be a constant, regardless of the length of the torque wrench. From the quotes above, Allan seems to acknowledge that the 0.8 value was arrived at based on a wrench length of 12 inches. It therefore stands to reason that if you use a different wrench that is NOT 12 inches long, (dont confuse the issue with cheater bars - I mean a DIFFERENT WRENCH) the multiplier will be something other than 0.8. You cant have it both ways - its either based on the wrench length or its not.

Somebody find the flaw in my logic and put this to rest. Funny how little things like this can gnaw at you late at night when you should be sleeping...

erich
 
I will try this one more time. Forget the length of your wrench, Forget cheater bars and everything else. If you have a torque wrench that you currently use to torque things in foot lbs. and you want to torque a bolt to 100 foot lb. you set your wrench or reed your gauge at 100. If you use our prop wrench with your torque wrench and want 100 foot lbs. you set or read your torque wrench to 80 foot lbs. You do not need to do any math or calculations of any kind. We have done that for you. Allan:D
 
I will try this one more time. Forget the length of your wrench, Forget cheater bars and everything else. If you have a torque wrench that you currently use to torque things in foot lbs. and you want to torque a bolt to 100 foot lb. you set your wrench or reed your gauge at 100. If you use our prop wrench with your torque wrench and want 100 foot lbs. you set or read your torque wrench to 80 foot lbs. You do not need to do any math or calculations of any kind. We have done that for you. Allan:D

Allan... looks like the design has stirred up the math. I get it. Thanks for another Great Product! :)
 
The constant is the 3 inch extension. The torque is applied to it, not the nut.

Stimulating discussion
 
AC 43.13 is the bible, until someone can show me the math to prove it is incorrect (which I seriously doubt will happen), I will continue to go with the formula 43.13 shows with the exact length of my wrenches.

PS: I also ordered one of the wrenches, you can never have enough tools!
 
AC 43.13 is the bible, until someone can show me the math to prove it is incorrect....
I can't do that, would you settle for the math to show you it's correct? ;)

A torque is a force x an arm. If I apply a force F on a wrench L feet from a nut I will get a torque of T1:

F*L=T1

If I add an extension x feet long to the wrench and apply the same force F to the wrench handle I will get a different torque T2:

F*(L+x) = T2

Presumably T2 is the torque I really want. I would still measure a torque of T1 at distance L, the 'head' of the torque wrench. Think of this as the wrench setting, the wrench will 'click' (or indicate) when the torque at the head = T1 if the wrench is set to T1, but the torque at the extension will be T2. So...divide the first equation by the second:

F*L/[F*(L+x)] = T1/T2

The force cancels, move the bolt torque to the other side and get:

T1 = T2*L/(L+x)

Or as Walt put it:

Wrench setting = desired torque x wrench length / (wrench length + extension length)

I have two torque wrenches, one is ~10" to grip center, the other 14". If I use a 0.8 correction for a 3" extension on both I *will* get different torques at the fastener for the same torque setting.
 
Walt is correct, .8 is not a constant

Here's a simple diagram that shows the math. If the torque wrench is one foot long and the extension is 3in and installed in line with the handle then the .8 multiplier is correct if the wrench is two feet the multiplier would be .88 and if the wrench was three feet the multiplier is .92....if the extension is at an angle to the handle then the actual length E must be measured and used in the equation.

torque-proof-1.jpg


Here's a good calculator:

http://www.norbar.com/calculators/torque-wrench-extension-calculator.aspx

P.S. the wrench is awesome and I will definitely add one tot the tool box.
 
I'm just glad I already got my order in. Pretty sure Allan will be doubling the price tomorrow after all these posts :) These VAF guys are a bunch of tough customers huh? Just having a good product isn't enough any more.

Erich
 
Length does matter

I agree with Allan. If a cheater bar is used to extend the length of any length torque wrench...........at the handle end, then the torque value remains the same.

But with an extension between the torque wrench and the bolt, there are two places where you need to know the torque: the head of the torque wrench, and the bolt. You care about the first one because that is what the torque wrench is reading, and you care about the second one because that's the torque you are applying to the bolt. Adding a cheater bar changes the torque at the two places differently, because the lever arm ratios are different, which is why you have to pay attention to "wrench length" when using an extension, even if you don't have to when you aren't using an extension.

Suppose I have a 12" torque wrench, with Allan's 3" extension on a bolt, and I apply 100 lbs at the tail end of the torque wrench. The torque wrench reads 1 ft * 100 lbs = 100 ft lbs, and the bolt gets 1.25 ft * 100 lbs = 125 ft lbs. So the wrench is reading 0.8 of the bolt torque.

Now suppose I add a 15" cheater bar, and apply 50 lbs to the end of it. At the bolt, I've doubled the arm and halved the force, so it is seeing 2.50 ft * 50 lbs = 125 ft lbs., same as before. But the torque wrench head is now seeing, and reading, 2.25 ft * 50 lbs = 112.5 ft lbs. The wrench is reading 112.5/125 = 0.9 of the bolt torque.

Which is what you get from the formula (wrench length)/(wrench length + extension), where wrench length now is 12" + 15" = 2.25ft. Length does matter.

--Paul
 
Length does NOT matter

The reason length doesn't matter is that the torque wrench is indicating the torque on the nut, and not the force on the end of the wrench.

A wrench handle can be any length, and if the torque reading is calibrated at the nut end of the wrench, it will tell you the torque on the nut, which is what you want.

So, wrench #1 is 10 feet long, with a dial that indicates ft-lbs (or more correctly lb-ft) at the NUT. if you want 100 pounds of torque, you would apply a force of 10 lbs at the handle, and the dial would read 100. (10 feet X 10 lbs = 100 ft-lbs)

Wrench #2 is 1 foot long, with a dial that reads torque at the NUT. If you want 100 lbs of torque, you would apply a force of 100 lbs at the HANDLE, and the dial would read 100. (1 foot X 100 lbs = 100 ft-lbs)

You guys are confusing the nut torque with the force needed at the handle.

All torque wrenches read TORQUE AT THE NUT, not force on the end of the handle.

That's why the length of the handle doesn't matter for torque wrenches.

Taking all bets! :)
 
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What a "torqueing" point

And here we are back at what Allan said right at the beginning. He has done the math for us and in order to achieve the desired torque on the nut one would have to set the wrench at .8 of whatever ft-lbs you require. The reason is that the point of torque on the nut has been moved by 3'' which will always remain the same as long as you are using Allan's prop wrench. In other words the torque wrench will "click" at the correct torque setting regardless of the length of the handle. If however, you were using an ordinary flat or ring spanner and extended the handle it would be a very different story!!:eek:
 
*sigh*

If I have a 12" torque wrench and I apply a 80 lb force at the grip there will be a 80 ft-lb torque at the head. If I add a 3" extension (0.25 ft) straight out from the head that 80 lb will still produce 80 ft-lb at the head but it will produce 100 ft-lb at the end of the extension. That's what everyone wants. Problem is, if I use an 18" wrench, I will apply a 53.3 lb force at the handle to get 80 ft-lb at the wrench head. The torque at the bolt will be 53.3lb*(1.5+0.25 ft), or 93.3 ft-lb.

Might be within tolerances, might not. It's better to know than to guess.
 
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